CyberHunter
LinkedIn profile - Bastien Cordier Email: contact@bastiencordier.pro
// Other services

Port 128: GSS X License Verification

Port 128 is assigned by IANA to gss-xlicen (GSS X License Verification).

128

How gss-xlicen works

Other services
client:128gss-xlicenresponse client:128gss-xlicenresponse

The client sends a request to port 128 and the gss-xlicen service answers.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Well-known (0-1023)
Category
Other services
01 Security

Is port 128 dangerous?

We have no specific security note for port 128. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 128

ServicePortTransportDescriptionReferenceUpdated
gss-xlicen 128 TCP, UDP GSS X License Verification - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 128, and is it reachable?

Linux

sudo ss -ltnup 'sport = :128'      # process listening on 128
sudo lsof -nP -i :128

macOS

sudo lsof -nP -i :128

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 128 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 128
netstat -ano | findstr :128

From another machine

nmap -p 128 -sV <host>
sudo nmap -sU -p 128 <host>
nc -zv <host> 128

Block it in the firewall

sudo ufw deny 128/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 128" -Direction Inbound -LocalPort 128 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 128 used for?

Port 128 is assigned by IANA to gss-xlicen (GSS X License Verification).

Is port 128 TCP or UDP?

Port 128 is registered for TCP and UDP.

Is it safe to open port 128?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Close the port if nothing on the host needs it.

How do I check if port 128 is open?

On Linux run "ss -ltnup 'sport = :128'", on macOS "lsof -nP -i :128", and on Windows "netstat -ano | findstr :128" to see the local process. From another machine, "nmap -p 128 <host>" shows whether it is reachable.

05 Related
:4444 Metasploit default / krb524 tcp · udp · high risk :31337 Back Orifice / elite tcp · udp · high risk :1 TCP Port Service Multiplexer tcp · udp :5 Remote Job Entry tcp · udp :9 Discard tcp · udp · sctp · dccp :11 Active Users tcp · udp :17 Quote of the Day tcp · udp :18 Message Send Protocol (historic) tcp · udp

Latest vulnerability news

All news